
<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <meta http-equiv="X-UA-Compatible" content="ie=edge">
        <title>Document</title>
        <style>
            *{
                margin: 0px;
                padding: 0px;
                list-style:none;
            }
            div{
                width: 520px;
                height: 280px;
                margin:100px auto;
                position: relative;
                overflow: hidden;
            }
            ul{
                width: 9999px;
            }
            ul li{
                float: left;
            }
            ol{
                position: absolute;
                bottom:20px;
                left: 50%;
                transform: translateX(-50%)
            }
            ol li{
                width: 8px;
                height: 8px;
                background:white;
                border-radius: 50%;
                margin:0px 4px;
                float: left;
                cursor: pointer;
            }
            span{
                position: absolute;
                background:lime;
                top:50%;
                transform: translateY(-50%);
                cursor: pointer;
            }
            span:nth-of-type(1){
                left: 10px;
            }
            span:nth-of-type(2){
                right: 10px;
            }
            .current{
                background:lime;
            }
        </style>
    </head>
    <body>
        <div id="wrap">
            <ul id="box">
                <li>
                    <img src="images/pic1.jpg" alt="">
                </li>
                <li>
                    <img src="images/pic2.png" alt="">
                </li>
                <li>
                    <img src="images/pic3.jpg" alt="">
                </li>
                <li>
                    <img src="images/pic4.jpg" alt="">
                </li>
            </ul>
            <ol id="list">
                <li class="current"></li>
                <li></li>
                <li></li>
                <li></li>
            </ol>
            <span id="left">左</span>
            <span id="right">右</span>
        </div>
        <script>
            var box=document.getElementById('box');
            var wrap=document.getElementById('wrap');
            var right=document.getElementById('right');
            var left=document.getElementById('left');
            var list=document.getElementById('list').children
            var num=0;
            var timer;
            function fn(){
                timer=setInterval(function(){
                num++;
                if(num>3){
                    num=0;
                }
                var t=-num*520;
                    box.style.transform='translateX('+t+'px)';
                    for(var j=0;j<list.length;j++){
                        list[j].className='';
                    }
                    list[num].className='current'
                },1000)
            }
            fn()
            wrap.onmouseenter=function(){
                clearInterval(timer)
            }
            wrap.onmouseleave=function(){
               fn()
            }
            for(var i=0;i<list.length;i++){
                list[i].index=i;
                list[i].onclick=function(){
                    for(var j=0;j<list.length;j++){
                        list[j].className='';
                    }
                    this.className='current';
                    num=this.index;
                    var t=-num*520;
                    box.style.transform='translateX('+t+'px)';
                }
            }
            right.onclick=function(){
                num++;
                if(num>3){
                    num=0;
                }
                var t=-num*520;
                    box.style.transform='translateX('+t+'px)';
                    for(var j=0;j<list.length;j++){
                        list[j].className='';
                    }
                    list[num].className='current'
            }
            left.onclick=function(){
                num--;
                if(num<0){
                    num=3;
                }
                var t=-num*520;
                    box.style.transform='translateX('+t+'px)';
                    for(var j=0;j<list.length;j++){
                        list[j].className='';
                    }
                    list[num].className='current'
            }

        </script>
    </body>
</html>